Police said those taken to hospital were in a "serious condition" while Kent Fire and Rescue Service said two children had been released from one of the cars.

Hundreds of motorists were left stranded in traffic for several hours following the pile-up, according to the Red Cross, which sent emergency teams to the scene.

A spokesman said: "Fire and emergency response volunteers are on hand to provide food, water and first aid where needed to people caught in the congestion."

Chief Inspector Matt Kendall said anyone who saw the events leading up to the collision, or the crash itself, and who had since left the scene without speaking to police, should call the Serious Collision Investigation Unit on 01622 798538.